A series of metal chelating molecules, including the natural product mycelianamide and analogues of enterobactin, will be synthesized. Two main objectives will be pursued in the course of our investigation: 1. The elucidation of factors which govern the stability, chirality, and metal oxidation state of catechol and hydroxamate iron complexes. This objective will require the development of synthetic routes to a broad range of ligand systems. 2. The determination of ligand structural features which facilitate transport of chelated iron and the subsequent release of iron in microbial systems. The mapping of the bacterial enterobactin receptor in this way will allow the design of antibiotics which, upon chelation of iron, will be actively transported into the bacterial cell.